1. Field of the Invention
This invention relates generally to semiconductor fabrication. More specifically, the invention relates to producing water for use in the fabrication of semiconductors.
2. Description of the Related Art
Ultra-pure water plays an important role in the fabrication of semiconductors. One such role is the thermal oxidation of silicon, wherein a silicon dioxide (SiO2) film is grown on a silicon substrate by oxidizing the surface of the silicon substrate. Thermal oxidation of silicon proceeds much faster in the presence of water. Thus, the advantages are shorter process time and oxidation at a lower temperature as compared to dry oxidation.
Other examples of uses of ultra-pure water during semiconductor fabrication include repairing gate oxide material damaged during plasma etching via source/drain reoxidation; forming of “hard” oxides or SiOxNy; accomplishing cell reoxidation of high dielectric materials; wet cleaning/wet etching; in situ chamber cleaning for furnace; LPCVD; PECVD; HDP processing chambers and etch chambers; plasma etching; removing organic material such as in photoresist “ash” applications; and forming silicon oxides or silicon oxynitrides in steam plasma systems.
Pure water is required in each of these fabrication processes to avoid contaminating the fine integrated circuit devices and wiring. As devices are continually scaled down, purity requirements become even more stringent and important to the fabrication of operable high-speed circuitry.
Accordingly, there is a need for an efficient and reliable process for producing water having a high degree of purity for use in semiconductor fabrication processes.